The present invention relates to a gas turbine engine, and more particularly to process tooling and procedures to machine curved blade retention slots within a rotor disk.
A gas turbine has a multiple of rotor blades that may be secured to a multiple of rotor disks. The blade/disk attachment configurations utilize a convoluted attachment section complementary to a convoluted slot in the rotor disk periphery.
Various manufacturing methods have been used or proposed to efficiently form the blade retention slots. The most common method of manufacturing blade retention slots is a broaching process. Although effective, broaching of nickel based super alloys typical of a rotor disk may induce material strain hardening, surface microstructure alteration and slot deformation. Aside from the relatively high cost of the broach tools and limited tool life, part scrap rate may increase due to the defected surface integrity. Furthermore, broaching processes only generate straight slots.
Curved slot attachment configurations in highly cambered turbine airfoils minimize platform overhang and optimize stress distribution to reduce centrifugal forces, bending moments, vibrations and peak stresses. Curved slot attachment configurations, however, may be difficult to produce and are not readily produced through broaching processes.